Digital Load Cells vs. Analog Load Cells

High precision weight measurement is becoming a necessity for every industry and application. The competitive business environment requires a company to be as lean and mean as possible. Cutting fat means cutting costs and if you have a scale, using an ultra-precision scale can help a company shave pennies off packaging and shipping costs, formula ingredients, and many more things. Those pennies can add up and help a company maintain a competitive pricing edge. To understand how Arlyn Scales can give you precision accuracy, let’s discuss the difference between analog load cells and digital load cells.

Analog Load Cells

The leading analog load cell is called a strain gauge load cell. It measures the stress and strain of the load on the platform. Strain gauges are special resisters that are bonded to a spring element. The element bends when a load is placed on the scale platform. This causes the strain gauge resistors to stretch specific amounts, which changes their resistance. The resistors are wired together into the form of a Wheatstone Bridge. This means that a change in resistance changes the voltage coming from the bridge. The voltage signal is typically sent along a wire to the digital indicator. An Analog to Digital (A/D) converter changes the voltage reading to a digital value and the microprocessor in the digital indicator then uses that value to determine the weight that is on the scale platform. Now, the voltage signal that comes from the load cell and through the wire can be subject to interference from the work environment. This can cause inaccuracies when the A/D converter creates the digital value. Some manufacturers and engineers have put the converter right at the load cell, hoping this would end the interference issues. It can reduce errors in some situations, but not very significantly. While it is often given the title of Digital Load Cell, it is still just an analog load cell with a digital converter.

Digital Load Cells

Arlyn Scales has developed an internationally patented line of Ultra Precision scales, using a technology called Surface Acoustic Wave (SAW). The SAW load cells deployed in our scales do not use strain gauges. These load cells measure displacement rather than stress and strain. Solid state transducers are used instead and the frequency of the transducers changes as the weight on the platform changes. Since the frequency is already a digital signal, and the microprocessor measures this signal digitally, the precision is inherently better by an order of magnitude, and the interference problems seen in strain gauge load cells are eliminated.

Additional Strain Gauge Issues

The strain gauge load cell is constructed with sections of thin metal so that the strain gauges are sensitive enough to generate an accurate signal. However, this makes the spring element fragile and vulnerable to damage from shock loading or overloading. Shock loading is what happens when a load is dropped from a height on to the scale platform. Over loading happens when a load beyond the scale’s capacity is placed on the scale platform. When damage occurs, the scale’s accuracy is compromised. At that point, the scale must be taken out of service for repair. This takes time and costs money. Meanwhile, your company loses productivity until a replacement, or the repaired scale, can be put into service.

SAW Scale Solution

Since SAW load cells are measuring the displacement of the sensor due to the load on the platform, they are able to be constructed out of a thicker more durable metal. This allows the load cells to be more abuse resistant and less vulnerable to shock loading or over loading. Additionally, our innovative technological breakthrough enables our Ultra Precision scales to measure far beyond what is typical for high resolution scales. Normally, the kind of accuracy seen out of a high resolution scale, such as a force motor scale, would be limited to weight of 50 lbs. or less. This kept precision measurement mostly in the laboratory, computer industry, or small scale production for formulated items like pharmaceuticals, paints, and petrochemicals. Our SAW scales are capable of providing high resolution and high accuracy up to 500 lbs. With an Arlyn Ultra Precision SAW scale, you will be able to have precision accuracy at an industrial size. With our optional setpoint controller, you can program your scale to add specific amounts various component parts to create the total batch of your product. And with our computer connectivity options, you will be able to analyze and refine your automated process and procedure so you are not wasting an ounce of material. By cutting down waste and human error while simultaneously increasing automated speed and consistency, you will be surprised how much money you can save.

Old Fashioned Customer Service

Arlyn Scales creates the highest quality scales for growing companies around the world. We have been leaders in the weighing industry for the past thirty years. We focus on developing precision accuracy for all industries regardless of the capacity. Our research and development division works on technological advancements to create better load cells and other component parts to achieve this goal. We also pay an enormous amount of attention to the durability of our scales. Our scales are manufactured right next door to our offices in Long Island, New York. The fact that both our office and our factory are next to each other allows us to ship factory direct to our customers. This reduces our need for distributors, which means our customers get exceptionally low prices. The savings that we get by eliminating distributors gets rolled right back into our manufacturing process. These means our customers get an even better scale at a lower price. At Arlyn scales, we are a bit old fashioned and we think the human connection is important. When you talk with us, you’re not talking to a machine; you’re talking to one of our highly trained customer service staff. They are courteous, friendly and reliable. They will be able to help you get answers for your questions and guide you through the process of determining what scale is the best fit for you. If our standard models do not quite meet your company’s expectations, we will gladly sit down with you, discuss various options, and create a customized scale for you. Fill out the form on our Contact Us page or call us at (800) 645-4301 to learn more about our digital scales or for help selecting the model that best suits your needs.